The present invention relates to a new and improved apparatus forming folds in sheet material.
It has been suggested that a folder could be constructed in the manner disclosed in U.S. Pat. No. 2,039,335. This folder includes a chopper folder. A sheet is registered relative to a movable blade in the chopper folder by engagement with a stop. Therefore, movement of the sheet through the folder is interrupted. Of course, interrupting movement of the sheet through the folder is detrimental to high speed operation of the folder.
It has also been suggested that a folder could be constructed in the manner disclosed in U.S. Pat. No. 200,838. In this patent, sheet material from a printing press is engaged by a gripper connected with a tape. As the sheet material is moved by the gripper, a folding blade engages the sheet material and it is gripped by a folding roll. The folding roll cooperates with another roll to fold the sheet material. The sheet material is again folded by being moved between inner and outer shields by tapes.
Still another suggestion for the construction of a folder is disclosed in U.S. Pat. No. 4,747,817. In this patent, a shingled stream of signatures moves between upper and lower conveyor belts which accelerate each signature in turn. As the signatures are moved by the conveyor belts, they are folded downwardly on opposite sides of the conveyor belts by a cam means or former. The folded sheet material then enters a nip between a second pair of conveyor belts which crease or crimp the fold and change the orientation of the signatures from a vertical orientation to a horizontal orientation. The signatures are discharged from the second set of belts in a lapped stream which is re-oriented or turned through 90.degree. from the original flow path of the sheet material.